Hey guys, I also posted over on snipershide, but I wanted to get some of your expertise as well.
I've been trying to figure out where my bullet run out is coming from. I tested my fully prepped necks and most of them I can get to no more than .001" TIR on the necks.
I'm using a redding comp seater, and after seating my bullet runout varies from .001 to as much as .007" TIR.
case prep as follows:
lapua brass, skim neck turned to neck thickness of .014-.0145"
hornady 208 amax
rcbs JR3 single stage press
redding shellholder held in place with rubber o ring
redding body die
Trim and chamfer on wilson trimmer and with vld tool
clean ID of necks with steel wool on bronze brush after tumble
redding comp neck bushing die (I also tried with a lee collet die and the neck runouts were higher, up to .002" TIR so I stuck it out with the redding bushing die)
redding comp seater, seat then rotate case 1/2 turn, then complete seating
a few things to note is that in using my wilson case trimmer I need to rotate the case holder to get the cut all the way around the case mouth. I basically rotate the case holder until there's no more cutting by the blades. Also, my vld trimmer in the wilson trimmer has been cutting unevenly, I have a k&M vld tool on order.
I've tried floating my dies and not locking down the locking ring but still to no avail. All my cases after seating measure .001" TIR or less on the necks but the bullets still measure anywhere from .002 to .007 TIR with the majority being in the .004-.006 zone.
Any thoughts would be great.
I also have a forster co-ax coming in the mail hoping that will help as well.
I have had the same issues with secant ogive bullets in my 7mm STW. I'm using the Redding Comp. seating die, I found that if I set the bullet in the case as close to perfect as possible, run it up until I feel the spring in the die just start to compress, then pull ithe case and started bullet out and check and adjust runout (firm sidepressure with a couple fingers will easily do the job if you don't get the bullet seated very far), and then complete seating with a few rotations of the case on the way up, that gets about 2/3rds of the rounds to 0.001" runout or less. With all the trouble this process is and a 65% "success" rate, it isn't a perfect soution but it is a significant improvement for me.
Since I have the same issue, I will sit tight and hope someone tells us a better way. One suspicion I have is that the seating die is desiged for a tangent ogive and the tip on the secant ogive if bottoming out in the die. At least my issue is with the VLD's.
I think you will enjoy your Forester press. It is all I have ever used. I personally have never checked runout, so take this for what it is worth.
-With VLD bullets, you may need to get a stem that is made for them for your dies.
-When seating a bullet, I seat the bullet, then turn it 180 degrees and seat it again. Don't no if it helps, but I have reloaded some pretty accurate ammo.
-I would do all neck chamfering and trimming and then reisize again to see if it helps.
-Also, try not to use the plunger button when you can
A discription of you reloading process might help find the problem. Are you running heavy neck tension, do you feel a difference in seating pressure on some cases than others, how far are you bumping the shoulder, ect ?
I don't trim them at first because they're already right at about 2.487" within .001"
expand with sinclair mandrel
neck turn with forster turner to .014"-.0145"
size in redding body die.
Redding bushing die .336" bushing for a final od neck of .335"
Redding comp seater with vld seater stem
208 hornady amax. (neck tension should be right around .001" Bullets don't budge at all even with firm pressure on the table.
(After firing 4 times I anneal the necks)
tumble wipe clean
clean inside of necks with steel wool
bump shoulders back .001-.002"
Size neck down with bushing die (Fired cases measure .339 to .3395" on the necks. Using the .336" bushing gets me right at .335" for a final neck od. Loaded neck OD is .336")
Trim and chamfer on the wilson trimmer (again, issue with un even chamfer on the wilson vld tool may or may not be a culprit here.)
BAck to the tumbler to remove remaining case lube.
After wards I run it back through the neck sizer for good measure, make sure nothing got dinged around in the tumbler.
Total runout on the case necks after all prep is no more than .001"
Charge then seat bullet half way rotate 180 degrees and finish seating.
I've tried floating the seating die and not locking down the lock ring and I also use a rubber o ring around my shellholder instead of the retainer pin to help the case self align.
results are still the same. .002-.007" TIR measured about 1/8" from the tip.
All the lapua brass that I measure for neck thickness variance out of 70 cases only 12 measured .0015" in neck thickness variance. All the rest were .001" or less.
Unless this first batch of 30 cases I loaded up had more cases in it with .002" or more of neck thickness variance to begin with??? Doesn't seem likely with lapua brass, and even so, would .002" of neck thickness variance cause up to .007" of TIR on a loaded round???
Thanks for the input guys. Let me know what you think about my loading procedure and if there's something I might be over looking.
With a OD of .335" and neck thickness of .0145" then the math would be:
for a bullet grip of .004"
That is a little strong. Perhaps if you used a .338" bushing for an OD of .337" (after springback) then you would get a bullet grip (or neck tension) of .002" and that might make a difference. A set of pin gauges
might give you a surprise on how the actual dimensions of the ID of the neck. It has surprised me sometimes.
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